Antenna arrangement and method relating thereto

Abstract

The present invention relates to an omnidirectional base station antenna arrangement with a number of antenna elements and a number of transceiver means for transmitting and receiving signals to/from a number of user stations. A feeding network is provided which comprises a number of phase ports, a number of which form first phase ports connected to a number of transceiver means for downlink communication and a number of which form second phase ports connected to a number of transceiver means for uplink communication. The feeding network comprises a number of antenna ports connected to antenna elements and the feeding network generates substantially independent, orthogonal signals to provide for phase diversity and the antenna elements are arranged to form at least one cylindrical array antenna. The invention also relates to a method of providing communication between an omnidirectional base station antenna arrangement with a number of antenna elements and a number of transceiver means and a number of user stations as well as to a method of providing for at least phase diversity transmission at an omnidirectional base station antenna arrangement.

1. An omnidirectional base station antenna arrangement comprising:
 a number of antenna elements forming a number of simultaneous omnidirectional radiation patterns; 
 a number of transceivers for transmitting and receiving signals to/from a number of user stations; and, 
 a feeding network comprising a phase port including first phase ports connected to a number of the transceivers for downlink communication and second phase ports connected to a number of the transceivers for uplink communication, said feeding network further comprising a number of antenna ports connected to antenna elements, which feeding network generates substantially independent, orthogonal signals to provide for phase diversity and in that the antenna elements are arranged to form at least one cylindrical array antenna. 
 
   
   
     2. An antenna arrangement according to  claim 1 , wherein performance on the uplink and on the downlink respectively is controllable through a number of phase ports that are arranged to form first and second phase ports respectively. 
   
   
     3. An antenna arrangement according to  claim 1 , wherein each first phase port is connected to one transceiver. 
   
   
     4. An antenna arrangement according to  claim 3 , wherein each transceiver is connected to a separate first phase port of the feeding network. 
   
   
     5. An antenna arrangement according to  claim 1 , wherein more than one transceiver is connected to one and the same first phase port for at least some of the phase ports. 
   
   
     6. An antenna arrangement according to  claim 1 , wherein a transceiver is connected to more than one phase port. 
   
   
     7. An antenna arrangement according to  claim 1 , wherein a number of signal splitters are provided for splitting signals output from the second phase ports on the uplink and wherein each second phase port in use is connected to one splitter. 
   
   
     8. An antenna arrangement according to  claim 7 , wherein at least two second phase ports for uplink communication are provided, each of said second phase port being directly connected to a separate signal splitter for enabling phase diversity reception. 
   
   
     9. An antenna arrangement according to  claim 8 , wherein each signal splitter is connected to each transceiver. 
   
   
     10. An antenna arrangement according to  claim 8 , wherein each splitter is connected to a number of transceivers which number may be different for a different splitter. 
   
   
     11. An antenna arrangement according to  claim 1 , wherein the number of phase ports in use generating orthogonal signals is lower than or equal to the number of antenna elements. 
   
   
     12. An antenna arrangement according to  claim 1 , wherein a common cylindrical antenna array is used for uplink and downlink communication. 
   
   
     13. An antenna arrangement according to  claim 1 , wherein separate cylindrical antenna arrays are used for uplink and downlink communication respectively. 
   
   
     14. An antenna arrangement according to  claim 13 , wherein at least two cylindrical antenna arrays are provided and wherein the feeding network comprises two feeding networks such that each cylindrical antenna array is connected to a separate feeding network, a first the separate feeding networks handling downlink communication whereby every phase port of the first feeding network is used as a first phase port, and a second of the separate feeding networks handling uplink communication, each of a number of phase ports communicating with a number of transceiver means via separate splitter. 
   
   
     15. An antenna arrangement according to  claim 12 , wherein at least one cylindrical antenna array is used for downlink communication and at least two cylindrical antenna arrays are used for uplink communication to provide for space diversity. 
   
   
     16. An antenna arrangement according to  claim 12 , wherein at least one dual polarized antenna array is used to provide for polarisation diversity. 
   
   
     17. An antenna arrangement according to  claim 1 , wherein a number of phase ports are used both as first and second phase ports for both uplink and downlink communication and in that said phase ports are connected to duplex filters. 
   
   
     18. An antenna arrangement according to  claim 1 , wherein the feeding network comprises a unitary orthogonal scattering matrix. 
   
   
     19. An antenna arrangement according to  claim 18 , wherein the feeding network comprises a Butler matrix. 
   
   
     20. An antenna arrangement according to  claim 18 , wherein the antenna arrangement comprises a cylindrical array antenna with antenna elements arranged in N columns or subarrays which are fed through the/a matrix to give maximum N orthogonal phase ports. 
   
   
     21. An antenna arrangement according to  claim 20 , wherein spacing between the columns is approximately λ/4–2λ, λ being the signal wavelength. 
   
   
     22. A method of providing communication between an omnidirectional base station antenna arrangement, comprising a number of antenna elements, forming a number of simultaneous omnidirectional radiation patterns, and a number of transceivers, and a number of user stations,
 the method comprising the step of: 
 connecting the transceivers to a number of phase ports of feeding network such that only a limited number of transceivers are connected to each phase port; 
 transforming signals from the transceivers in the feeding network into signals which are substantially independent and orthogonal to provide for phase diversity, 
 transforming signals from the transceivers in the feeding network into signals which are substantially independent and orthogonal to provide for phase diversity, 
 putting out the orthogonal signals having different phase but similar amplitude on antenna ports to a number of antenna elements arranged to form at least one cylindrical array antenna. 
 
   
   
     23. The method of  claim 22 , further comprising:
 connecting each transceiver to a separate phase port of the feeding network for downlink communication. 
 
   
   
     24. The method of  claim 22 , further comprising:
 feeding the cylindrical antenna array comprising antenna elements arranged in N columns through a feeding network comprising a Butler matrix wherein the column spacing is λ/4–2λ such that an omnidirectional phase pattern is obtained containing N cycles of phase variation. 
 
   
   
     25. The method according to  claim 22 , further comprising:
 connecting at least two phase ports of the feeding network to an uplink splitter, 
 connecting the uplink splitter to at least a number of the transceivers such that phase diversity reception is enabled. 
 
   
   
     26. The method according to  claim 25 , further comprising:
 controlling a relationship between uplink and downlink performance through controlling the number of phase ports used for uplink and downlink communication respectively. 
 
   
   
     27. The method according to  claim 22 , further comprising:
 providing another cylindrical antenna array, 
 connecting said other antenna array to a second feeding network, 
 connecting at least some phase ports of the second feeding network to signal splitters, 
 connecting each of said splitters to at least some of the transceivers respectively such that phase diversity reception is enabled. 
 
   
   
     28. The method according to  claim 22 , further comprising:
 connecting some of the phase ports to signal splitters for uplink communication, (via duplex filters) 
 connecting each of said splitters to at least some of the transceivers respectively such that phase diversity reception is enabled. 
 
   
   
     29. The method according to  claim 22 , further comprising providing additional antenna arrays and feeding networks to enable polarisation diversity and/or space diversity. 
   
   
     30. The method of  claim 22 , further comprising connecting at least some transceivers to two or more phase ports to enable beamforming and different modulation of signals. 
   
   
     31. A method of providing at least phase diversity transmission at an omnidirectional base station antenna arrangement comprising a number of antenna elements, forming a number of simultaneous radiation patterns, and a number of transceivers, wherein the method comprises:
 providing signals from the transceivers to a number of phase ports of a feeding network such that only a limited number of the transceivers are connected to each phase port; 
 transforming signals from the transceivers in the feeding network into signals which are substantially independent and orthogonal, 
 outputting the orthogonal signals having different phase(s) but similar amplitude(s) on output ports to a number of antenna elements arranged to form a cylindrical array antenna. 
 
   
   
     32. An antenna arrangement according to  claim 1 , wherein the antenna arrangement generates omni-directional beams.